Metal wire is a material that has a wide variety of uses in many applications. One method of producing wire products involves drawing a wire stock through one or more dies to provide a wire having a desired outer diameter However, in the drawing process, the molecular arrangement of the atoms in the wire may be affected so that the drawn wire product may have certain undesirable characteristics.
More specifically, the drawn wire may not have a desirable "cast". Also, the drawn wire may have an undesirable "helix" characteristic. To one of ordinary skill in the art of wire drawing, the term "cast" refers to the characteristic of a short piece of drawn wire to assume a curved orientation of a specific radius of curvature. Even for drawn wire wound on a spool, if a short piece of the wire were cut from the spool and permitted to sit undisturbed on a flat surface, such as a tabletop, the short piece of wire would inherently curve to a radius of curvature indicative of its "cast".
Also, to one familiar with the art of wire drawing, the "helix" characteristics of the wire may be of great importance. If a short piece of drawn wire is placed on a flat surface, the ends of the wire may lie flat on the surface, or the ends may tend to bend either upward or downward out of the plane of the flat surface. The degree to which the ends of the wire bend out of the plane of the flat surface is referred to as the "helix" characteristic of the wire. If the tendency of the ends of the wire to bend out of the plane of the flat surface is eliminated, then the helix of the wire is said to be eliminated. When the helix is eliminated, the two ends of the piece of drawn wire placed on the flat surface lie in the same plane, and could abut one another if pushed together in the same plane.
Various applications for drawn wire (e.g. for conveyor belts and radial tires) have stringent requirements with respect to the cast and the helix of the wire in addition to the diameter of the wire. More specifically, some applications for drawn wire call for elimination of the helix characteristic. However, conventional wire drawing processes do not provide for consistently eliminating the helix characteristic.
Presently, steps taken to eliminate the helix characteristic of drawn wire are inconsistent and not reproducable. For example, in a production run of drawn wire, at the beginning of the run, a sample of wire may be taken and tested for its helix characteristic. If the helix characteristic is not as desired, then adjustments are made in the drawing or cast control steps to adjust the helix to the desired degree. Once the desired helix is obtained, the production run is continued. However, at intervals during the production run, if new samples are taken and tested for helix, often the helix characteristics will have changed and be out of required specifications. Under present conditions, vast quantities of wire are wasted because of unpredictable and uncontrolled variations in wire helix characteristics of drawn wire. Presently, there is a great need for a device that can provide consistent helix control for drawn wire.
With respect to the characteristic of cast, a drawn wire is often pulled through a series of rollers which impart a desired cast to the wire. Different rollers may be used for different wires. Furthermore, optimum spacing and alignment of the rollers may be attained only after a time-consuming and expensive series of trial and error. So when one wire is substituted for another, a given set of rollers may have to be changed, or a given set of roller alignment and spacing parameters may have to be changed, followed by extensive trial and error to obtain optimum spacing and alignment characteristics for producing desired wire. It would be desirable to be able to change roller sizes, alignment, and spacing without requiring extensive trial and error to obtain desired cast characteristics in drawn wire.
Also, the prior art merely bows the wire and does not consistently (and substantially) break down the molecular structure or composition of the wire, so that the cast of the wire is not uniformly maintained using the prior art method.